Definition of sump
1
: a pit or reservoir serving as a drain or receptacle for liquids: such as
a
: cesspool
b
: a pit at the lowest point in a circulating or drainage system (such as the oil-circulating system of an internal combustion engine)
3
[German Sumpf, literally, marsh, from Middle High German — more at swamp]
a
: the lowest part of a mine shaft into which water drains
b
: an excavation ahead of regular work in driving a mine tunnel or sinking a mine shaft
4
: something resembling a sump : sink 2
